This invention relates generally to devices that attach to power tools and dispense fluid on a work surface, and more particularly to thumb-operated devices that attach to hand-held polishers wherein a work facilitating or enhancing liquid is dispensed from the devices onto surfaces to be polished or buffed.
Hand-held surface finishing power tools, such as hand-held rotary polisher 102 in FIG. 1, are well-known in the art. Rotary polishers are often used by original equipment manufacturers, auto body shops, and professional detailers to sand, polish, or otherwise finish surfaces on vehicles such as automobiles, recreational vehicles, boats, aircraft, and other vehicles. Rotary polishers can be used for polishing other surfaces as well, such as those on buildings, bridges, and other structures. Rotary polishers are sometimes called rotary buffers, variable speed buffers, buffing or polishing machines, circular polishers, or orbital polishers. Some exemplary rotary polishers include the DeWalt DW849 7″/9″ Electronic Variable Speed Polisher, Milwaukee 5460 7/9 in. Dial Speed Control Polisher, Makita 9227C 7″ Electronic Sander-Polisher, and Porter Cable 7424 6″ Variable-Speed Random-Orbit Polisher.
Rotary polisher 102 includes rotatably attached finishing disk 104 comprising disk-like backing pad 112 upon which a buffing pad 106 can be placed. While a user holds the polisher against a work surface, the polisher rotates the buffing pad against the work surface at a range of angular velocities depending upon the model, e.g., 600, 1000, 1800, 3000, or 3600 revolutions per minute (RPM). Some models of buffing machines have variable speeds which allow a user to control the angular velocity or rotation speed of the tool. Some models have an adjustable governor setting which limits rotation speed, which can be used for more sensitive operations where too much speed could cause damage to the work surface. Non-rotary surface finishing power tools are also available, such as those that vibrate a pad or employ a belt.
On many hand-held polishers, the speed of the device is controlled by a trigger switch on a handle, such as speed control trigger 108 on handle 110 of polisher 102. The placement of speed control trigger 108 allows a user to grip handle 110 with one hand and comfortably depress speed control trigger 108 with the same hand's index finger, thereby allowing an uninterrupted grip of handle 110. The user's other hand can hold a handle (not shown) on the distal end of the polisher to direct and stabilize finishing disk 104 on a work surface.
On other hand-held polishers, such as those for home use, the speed of the device is controlled by a switch integrated into the main housing of the polisher. There may be several speed selections, or simply an ‘on/off’ switch. One grips the main housing, which is generally elongated and perpendicular to the normal of the polishing surface.
A wide variety of attachments can serve as finishing disk 104 on rotary polisher 102. Finishing disks can include sisal wheels, spiral sewn cotton wheels, loose cotton wheels, canton flannel wheels, acrylic buffing wheels, treated spiral sewn wheels, scrubber wheels, cushion buffs, denim buffing wheels, domet flannel wheels, expanding sander wheels, facer buffs, finger buffs, flap wheels, mushroom buffs, sanding drums, razor buffs, scrubbing mushroom buffs, string buffs, vented buffs, treated vented buffs, and other finishing attachments. Circular buffing pad 106 wraps around rigid or semi-rigid backing pad 112, which can be made of rubber, phenolic resin, metal, or other types of suitable material. A backing pad is sometimes called a back-up plate. Because of the way buffing pad 106 wraps around backing pad 112, buffing pad is sometimes called a polishing bonnet. Other styles of buffing pads include those that attach to the backing pad by hook-and-loop fasteners (e.g., VELCRO®). Buffing pad 106 can be made of soft fabric, such as cotton, wool, nylon, or foam and are often between ⅞ and 1¼ inches thick.
Power polishers and sanders are somewhat interchangeable, depending on the job. By attaching a fine sanding disk to rotary polisher 102, the polisher can sand a surface.
The finishing pad employed often depends upon the material of the surface to be finished (e.g., aluminum, fiberglass, clear-coat), the stage of surface finishing, the ending smoothness required, the speed at which a customer requires work to be completed, the liquid polish used, cost, and other like factors. The same factors dictate the size of the pads employed. Pads come in various sizes, for example in 4, 5, 5¼, 6, 7, and 12-inch diameters.
During polishing, it is often desirable to apply a polishing compound to a surface to aide in polishing. The compound is often in liquid form, but can also be a general fluid form. In practice, liquid polish is often squirted from a bottle onto the work surface. Squirting the polishing liquid from a bottle usually involves a user stopping and setting down the buffing machine, picking up the bottle, squirting liquid polish onto the surface from the bottle, then picking up the buffing machine and restarting it. Such a process tends to be tedious and time consuming.
During sanding, water or oil can be applied to a work surface to reduce dust and lubricate and cool the tool and surface. Other fluids, such as air or inert gases can be dispensed (i.e., blown) on the surface for cooling as well.
Attempts have been made in the prior art to incorporate a liquid polish dispensing mechanism into a rotary polisher. However, such designs typically involve a redesign of the polisher so that components such as reservoirs, tubing, pumps, and nozzles can be plumbed inside the polisher. Also, integrated dispensers are not normally easily removed for cleaning. Some prior art designs dispense polish underneath the center of the buffing pad. However, with such designs it is difficult for an operator to see exactly when and how much product is dispensed when the finishing disk is held against the work surface and/or is spinning.
There exists a need for an improved liquid polish dispenser.